Catheter system and method for delivery of therapeutic compounds to cardiac tissue

ABSTRACT

This is a method and an apparatus for the treatment or introduction of contrast fluids into tissue, particularly cardiac tissue. The apparatus includes a catheter having an elongated flexible body and a tissue infusion apparatus including a hollow infusion needle configured to secure the needle into the tissue when the needle is at least partially inserted into the tissue to help prevent inadvertent removal of the needle from the tissue. This permits the selected treatment or contrast fluid to be confined to a specific site. The catheter may also include a visualization assembly including a transducer at the distal end of the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of Ser. No. 11/809,022, filed May 30,2007, entitled CATHETER SYSTEM AND METHOD FOR DELIVERY OF THERAPEUTICCOMPOUNDS TO CARDIAC TISSUE, which is a Continuation of U.S. Ser. No.11/081,284, filed Mar. 15, 2005, entitled CATHETER SYSTEM FOR DELIVERYOF THERAPEUTIC COMPOUNDS TO CARDIAC TISSUE, which is a Continuation ofU.S. Ser. No. 10/639,896, filed Aug. 12, 2003, entitled CATHETER SYSTEMFOR DELIVERY OF THERAPEUTIC COMPOUNDS TO CARDIAC TISSUE, which is aContinuation of U.S. Ser. No. 09/797,483, filed Feb. 28, 2001, entitledENDOCARDIAL INFUSION CATHETER, which is a Continuation of U.S. Ser. No.08/403,553, filed Mar. 14, 1995, entitled ENDOCARDIAL INFUSION CATHETER,which is a Continuation of U.S. Ser. No. 08/100,086, filed Jul. 30,1993, entitled ENDOCARDIAL INFUSION CATHETER, all of which areincorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

Abnormal heart beats or cardiac arrhythmias can cause significantmorbidity and mortality. These arrhythmias arise from a variety ofcauses, including atherosclerotic heart disease, ischemic heart disease,metabolic or hemodynamic derangements, rheumatic heart disease, cardiacvalve disease, certain pulmonary disorders and congenital etiologies.The normal heart rate is about 60 to 100 beats per minute. Arrhythmiasrefer to tachycardias at rates exceeding 100 beats per minute for aduration of at least 3 beats. Sometimes no treatment is required, suchas in the tachycardia following a physiologic response to stress orexercise. However, in some cases, treatment is required to alleviatesymptoms or to prolong the patient's life expectancy.

A variety of treatment modalities exist, including electric directcurrent cardioversion, pharmacologic therapy with drugs such asquinidine, digitalis, and lidocaine, treatment of an underlying disordersuch as a metabolic derangement, and ablation by either percutaneous(closed chest) or surgical (open chest) procedures. Treatment byablation involves destruction of a portion of cardiac tissue which isfunctioning abnormally electrically.

Normally the heart possesses an intrinsic pacemaker function in thesinoatrial (SA) node which is in the right atrium, adjacent to theentrance of the superior vena cava. The right atrium is one of fouranatomic chambers of the heart. The other chambers are the rightventricle, the left atrium, and the left ventricle. The superior venacava is a major source of venous return to the heart. The SA node is anarea of specialized cardiac tissue called Purkinje cells and whichusually measures roughly III centimeters by about 2 k millimeters. Anelectrical impulse normally exits from the SA node and travels acrossthe atrium until it reaches the atrioventricular (AV) node. The AV nodeis located in the right atrium near the ventricle.

Emerging from the AV node is a specialized bundle of cardiac musclecalls which originate at the AV node in the interatrial septum. This“bundle of His” passes through the atrioventricular junction and laterdivides into left and right branches which supply the left and rightventricles. The left and right bundles further give rise to brancheswhich become the so-called distal His-Purkinje system which extendsthroughout both ventricles.

Thus in a normal situation an impulse originates intrinsically at the SAnode, transmits through the atrium and is modified by the AV node. TheAV node passes the modified impulse throughout the left and rightventricles via the His-Purkinje system to result in a coordinatedheartbeat at a normal rate.

Many factors affect the heart rate in addition to the intrinsicconduction system. For example, normally the heart rate will respond tophysiologic parameters such as stress, exercise, oxygen tension andvagal influences. Additionally, there are multiple causes for anabnormal heartbeat such as an abnormal tachycardia. One group of suchcauses relates to abnormalities in the heart's conduction system. Forexample, ectopic or abnormally positioned nodes may take over the normalfunction of a node such as the SA or AV node. Additionally, one of thenormal nodes may be diseased such as from ischemic heart disease,coronary artery disease or congenital reasons. Similarly, a defect canexist in an important part of the conduction system such as the bundleof His or one of the bundle branches supplying the ventricles.

Treatment of abnormal tachycardias arising from ectopic foci orso-called ectopic pacemakers can include pharmacologic therapy orablative therapy. The ablative therapy may be accomplished bypercutaneous insertion of a catheter or by an open surgical cardiacprocedure.

Cardiac arrhythmias may be abolished by ablating the tissue responsiblefor the genesis and perpetuation of the arrhythmias. Steerable ablationcatheters using radio frequency (RF) energy are known. The RF energy canbe directed to the area to be ablated and causes destruction of tissueby heat. In addition, direct infusion of ethanol has been performedduring open heart surgery. Ethanol has also been infused into coronaryarteries to ablate a focus such as a ventricular arrhythmia focus or theAV node. Unfortunately this tends to result in a fairly large region ofcardiac tissue death or myocardial infarction. With transarterialinfusion there is difficulty in precisely controlling the location andextent of the ablation.

Thus, the prior art lacks catheters useful for direct endocardialinfusion of sclerosing agents at the precise location of tachycardia.The present invention addresses these and other needs.

SUMMARY OF THE INVENTION

The present invention is directed to methods and devices for delivery ofdesired compounds (e.g., ablation liquids) to cardiac and other tissueusing a novel hollow infusion needle. The needle is typically used toinject an ablation liquid endocardially to produce a more circumscribedlesion than that possible using prior art infusion techniques. Theneedle is designed such that it can be imbedded in and secured to thetissue to be treated.

Although ablation of cardiac tissue is a preferred use of the cathetersof the invention, they can be used to inject desired compositions for awide variety of uses. Virtually any therapeutic compound can bedelivered intracardially using the catheters of the invention. Forinstance, the catheters can be used to deliver compositions comprisingmodified genes to cardiac or other tissue for use in gene therapyprotocols. Methods for introducing a variety of desired polynucleotidesto target cells using, for example, retroviral vectors are well known.Examples of sequences that may be introduced include antisensepolynucleotides to control expression of target endogenous genes. Inaddition, genes encoding toxins can be targeted for delivery to cancercells in tumors. In other embodiments, homologous targeting constructscan be used to replace an endogenous target gene. Methods and materialsfor preparing such constructs are known by those of skill in the art andare described in various references. See, e.g., Capecchi, Science244:1288 (1989).

Other uses include intramyocardial delivery of isolated cells or cellsubstitutes. These approaches typically involve placement of the desiredcells on or within matrices or membranes which prevent the host immunesystem from attacking the calls but allow nutrients and waste to pass toand from the calls (see, Langer et al., Science 260:920-925 (1993)). Forinstance, sinus node cells can be implanted in a desired location totreat disorders in impulse formation and/or transmission that lead tobradycardia.

For use in ablation of cardiac tissue, the catheters of the inventionhave an elongated flexible body and a tissue ablation assembly having atissue ablation tip, at the distal end of the body. The distal end ofthe catheter is introduced into a cardiac chamber (or other body region)including the tissue to be ablated. The catheter may be equipped forstandard arrhythmia mapping, for example multiple electrodes may bepresent on the outside of the catheter for recording endocardialelectrograms. Alternatively, the catheter may include a visualizationassembly at the distal end of the body. The visualization assembly isused to position the tip of the catheter adjacent the tissue to beablated. Catheters comprising visualization and ablation means aredescribed in copending application, patent application Ser. No.08/099,995, now U.S. Pat. No. 5,385,148, which is incorporated herein byreference.

The tissue ablation assembly comprises a hollow infusion needle whichcan be extended or withdrawn from the distal end of the catheter. Thehollow infusion needles of the invention have a securing elementconfigured to engage tissue when the needle is at least partiallyinserted into the tissue to stop recoil and help prevent inadvertentremoval of the needle from the tissue. The securing element can beconfigured into the form of corkscrew or threads surrounding a straightneedle. Alternatively, the securing element can be configured as aplurality of pre-curved needles, which curve towards or away from thelongitudinal axis of the catheter. The pre-curved needles can also beused to deliver ablation compounds of desired. Other structures, such asbarbs, could also be used as the securing element. The hollow infusionneedle is preferably a corkscrew-shaped needle, with a tight curl. Thedistance between turns is preferably about 0.5 mm or less. Such a needleallows the practitioner to inject through layers by slowly extending theneedle, injecting, extending farther and injecting again.

When used to ablate tissue the catheter can be used with a conventionalablation compounds such as alcohol (e.g., ethanol), collagen, phenol,carbon dioxide and the like. The solution may comprise variouscomponents for other purposes as well. For instance, an echocontrastagent for echo imaging may be included. Collagen can also be bound to aniodinated molecule to make it radiodense. Alternatively, when used forgene therapy protocols, the catheters of the invention can be used tointroduce desired polynucleotides to the target tissue.

When performing a percutaneous or closed chest cardiac ablationprocedure using the catheters of the invention, fluoroscopy can be usedto visualize the chambers of the heart. Fluoroscopy uses roentgen rays(X-rays) and includes use of a specialized screen which projects theshadows of the X-rays passing through the heart. Injectable contrastagents to enhance the fluoroscopic picture are well known in the art andare not described in detail here.

Typically, the catheter is placed in an artery or a vein of the patientdepending on whether the left (ventricle and/or atrium) or right(ventricle and/or atrium) side of the heart is to be explored andportions thereof ablated. Frequently an artery or vein in the groin suchas one of the femoral vessels is selected for catheterization. Thecatheter is passed via the blood vessel to the vena cava or aorta, alsodepending on whether the right or left side of the heart is to becatheterized, and from there into the appropriate atrium and/orventricle.

The catheter is generally steerable and it is positioned against anendocardial region of interest. As mentioned above, the cathetertypically includes a means for sensing the electrical impulsesoriginating in the heart. Thus, the electrode catheter can provide anumber of electrocardiogram readings from different areas of theinternal aspects of the heart chambers. These various readings arecorrelated to provide an electrophysiologic map of the heart includingnotation of normal or abnormal features of the heart's conductionsystem. Once the electrophysiologic map is produced, an area may beselected for ablation.

Typically, before final ablation, the suspect area is temporarilysuppressed or deadened with a substance such as lidocaine or iced salinesolution. Subsequently the area is remapped and the heart reevaluated todetermine if the temporary measure has provided some electrophysiologicimprovement. If improvement has occurred, then the clinician may proceedwith permanent ablation typically using ethanol.

In one aspect, the present invention provides the novel combination oftissue ablation and tissue imaging in a single catheter to permitablation of tissue to be properly accomplished by the correct selectionof the ablation site and monitoring and controlling the ablation of thetissue being destroyed. The invention is preferably used with imagingultrasonic transceivers in an ablation catheter to provide real timeassessment of lesion volume and to monitor the tissue being ablated.Alternatively, one or more A-mode ultrasonic crystals can be used. Asused herein, a visualization means of the invention may be either animaging or an A-mode ultrasonic device. One or more transponder can alsobe used to assist in localizing the catheter tip.

Other features and advantages of the invention will appear from thefollowing description in which the preferred embodiments have been setforth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall view of a catheter made according to the invention;

FIG. 2 is an enlarged, simplified cross-sectional view of the distal endof the flexible body of FIG. 1;

FIG. 3 is an enlarged, schematic cross-sectional view of the distal endof the flexible body of FIG. 1 illustrating the general locations of thetip electrode, ultrasonic transducer, and ring electrodes;

FIG. 4 is an overall view of an alternative catheter made according tothe invention;

FIG. 5 is an enlarged, simplified cross-sectional view of the tip andthe catheter of FIG. 4, shown with a hollow needle retracted;

FIG. 6 is an external view of the tip of FIG. 5 with the hollow needleextended;

FIG. 7 is an enlarged view of the needle driver and infusion portmounted to the handle of FIG. 4.

FIG. 8 is an enlarged, simplified cross-sectional view of the tip of acatheter with a hollow needle retracted.

FIG. 9 illustrates the handle assembly of a catheter of the invention.

FIG. 10A is an enlarged, simplified cross-sectional view of the tip of acatheter with the anchoring needles and hollow needle in the retractedposition.

FIG. 10B is an enlarged, simplified cross-sectional view of the tip of acatheter with the anchoring needles and hollow needle in the extendedposition.

FIG. 10C is an end view of the catheter tip in FIG. 10B.

FIG. 11A is an enlarged, simplified cross-sectional view of the tip of acatheter with the anchoring/infusion needles in the extended position.

FIG. 11B is an end view of catheter tip in FIG. 11A.

FIG. 12 is an and view of a catheter tip with 10 anchoring/infusionneedles.

FIG. 13A is an enlarged, simplified cross-sectional view of the tip of acatheter showing the triggering mechanism with the anchoring/infusionneedles in the retracted position.

FIG. 13B is an enlarged, simplified cross-sectional view of the tip of acatheter showing the triggering mechanism with the anchoring/infusionneedles in the extended position.

FIG. 14 illustrates the handle assembly of a catheter of the inventionshowing the trigger for releasing and retracting the anchoring needles.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a catheter 2 having a handle 4 from which a flexiblebody 6 extends. Flexible body 6 extends from one end 8 of handle 4 whileultrasonic cable 10 and a combination electrode/thermistor cable 12extend from the other end 14 of handle 4. Distal end 16 of flexible body6 is steerable, as suggested by the dashed lines 18 in FIG. 1, in aconventional manner using a steering lever 20 mounted to handle 4. Lever20 which controls one or more steering cables 22, see FIG. 2, as isconventional. Distal end 16 has an RF transmitting tip 24 securedthereto. Transmitting tip 24 is connected to an appropriate RF energysource, not shown, through lead 26 which extends along flexible body 6,through handle 4 and through combined cable 12.

Tip 24 has a pair of axially extending bores 28, 30 formed from itsdistal end 32. Bore 28 is used to house an ultrasonic transducer 34while bore 30 is used to house a thermistor 36. Transducer 34 issurrounded by a thermal insulating sleeve 38, typically made ofinsulating material such as polyimide. The base 40 of transducer 34 hasa lead 41 extending from transducer 34, along flexible body 6, throughhandle 4 and through ultrasonic cable 10. The ultrasonic transducercomprises a piezoelectric crystal capable of operating at a standardfrequency, typically from about 5 to about 50 MHz. The crystal is formedfrom standard materials such as barium titanate, cinnabar, orzirconate-titanate. The transducer 34 generates an ultrasonic pulse inresponse to electrical impulses delivered through lead 41. Ultrasonicechoes are then received by the ultrasonic transducer 34 which generateselectrical signals which are delivered to the receiving unit (notshown). The transducer is connected to conventional transmitting andreceiving units which include the circuitry necessary for interpretingthe ultrasonic information and displaying the information on a visualdisplay. Signal processing may take advantage of change in tissuedensity or texture as correlated with lesion depth. The ultrasonicsignal can be visualized on a two dimensional echocardiograph or usingnon-imaging A-mode.

Base 40 of transducer 34 is sealed with a UV potting adhesive 42, suchas Tough Medical Bonder made by Loctite, to provide both thermal andelectrical insulation. The catheter also comprises an ultrasonictransponder 44, shown schematically in FIG. 3, spaced about 2.5 mm fromRF transmitting tip 24 at the distal end 16 of body 6. Transponder 44 isused to help in localization of the catheter tip as is known in the artand described in Langberg et al., JACC 12: 218-223 (1988). In alternateembodiments, multiple transponders can be used to help with assessingcatheter tip orientation as well.

In the embodiment of FIGS. 1-3, the ablation apparatus exemplified bythe use of RF transmitting tip 24. In addition to tip electrode 24,catheter 2 also includes three ring electrodes 46, 47, 48 positioned ina proximal direction, that is towards handle 4 relative to tip electrode24 and transducer 44. Electrodes 46-48 (spaced 2.5 ma apart) are used torecord electrical signals produced by the heart (electrocardiograms) forendocardial mapping using a multichannel EKG machine as is known n eart. Thermistor 36 is coupled to combination cable 12 through a lead 50extending from thermistor 36, to flexible body 6, through handle 4 andinto combination cable 12. Thermistor 36 is used to provide informationabout the temperature of the tissue at the distal end 32 of tip 24.

Separately, the above-discussed apparatus used to create ultrasonicvisualization of the tissue to be ablated is generally conventional. Andiscussed above, the ultrasonic visualization means may be used foreither imaging or A-mode. One such ultrasonic imaging system is sold byCardiovascular Imaging systems of Sunnyvale, Calif. Similarly, the RFablation system, used to ablate the tissue, is also generallyconventional, such as is sold, for example, by EP Technologies ofSunnyvale, Calif. What is novel is incorporating both the imaging andablation structure into a single catheter which permits real timevisualization and accurate positioning of the RP transmitter tip 24 withthe precise location to be ablated. The amount or volume of tissueablated can thus be constantly monitored during the procedure so thatneither too little nor too much tissue is ablated for maximum controland effectiveness. The use of temperature monitoring using thermistor 36is also generally conventional as well, but not in conjunction with anultrasonic imaging assembly. Instead of using RF energy to ablate thetissue, microwave radiation, laser energy, cryoblation or endocardialinjection/infusion, for example, can be used in conjunction withultrasonic transducer 34.

The use of catheter 2 proceeds generally as follows. Distal end 16 ofbody 6 is directed to the appropriate site using conventional techniquesand steering lever 20. Visualization of the tissue to be ablated andlocalization of the tip 24 is provided by ultrasonic transducer 34,ultrasonic transponder 44, and associated leads and cables coupled to aconventional ultrasonic imagining console, not shown. When tip 24 is atthe site of the tissue to be ablated, RF generator, not shown, coupledto combination cable 12, is activated to produce RF radiation at tip 24to ablate the tissue. The ablation is monitored by ultrasonic transducer34 as well as thermistor 36 to help ensure that the proper volume oftissue is ablated. When the proper volume of tissue is ablated, body 6is removed from the patient. Instead of the use of catheter 2 includingan RF transmitter tip 24, the catheter could use an ablation fluidinfusion tip similar to that shown in FIGS. 4-7. Also, preparatory tothe ablation sequence, the suspect area can be temporarily suppressed ordeadened using catheter 60 using lidocaine or iced saline solution, asdiscussed in the Background section above.

Referring the reader now to FIGS. 4-7, a catheter 60 is shown. catheter60 includes a handle 62 from which a flexible body 64 extends. Handle 62includes a steering lever 65 and combination infusion port 66 and needledriver 68 at the distal end 70 of handle 62. A pair of cables 72 extendfrom the proximal end 74 of handle 62. The distal end 76 of flexiblebody 64 has a tip assembly 78 mounted thereto. Tip assembly 78 includesmapping electrodes So connected to wires 82 which extend down flexiblebody 64, through handle 62 and to cables 72. Mapping electrodes 80provide the user with a nonvisual indication of where tip assembly is bymonitoring the electro-activity of the heart muscle, as is conventional.Electrodes So are electrically isolated from the remainder of tipassembly 78 by an insulating sleeve 84.

A hollow needle 86 is slidably mounted within a second insulating sleeve88 housed within insulating sleeve 84. The needle may be formed fromstandard metal alloys such as titanium alloy, stainless steel, andcobalt steel. The needle 86 is a corkscrew-shaped needle used to injectablating liquid into tissue and secure the needle to the tissue. Otherdesigns of hollow needles, including the use of barbs on a straight orcurved needle, can be used as well. While hollow needle 86 is shown suedwith a generally conventional mapping electrode type of catheter, itcould be used with an ultrasonic visualization assembly as shown inFIGS. 1-3, as well as other types of visualization assemblies.

A central bore 90 of hollow needle 86 is coupled to infusion port 66 byan infusion fluid tube 92 which extends along flexible body 64, throughneedle driver 68 and to infusion port 66. Threaded needle driver 68 isconnected to a tip extension 94 so that rotating needle driver 68 causestip extension 94 to rotate about the axis 95 of needle 86 and to moveaxially within flexible body 64. This causes hollow needle 86 to rotateabout axis 95 and to move axially within sleeve 88 from the retractedposition of FIG. 5 to the extended position of FIG. 6.

Rotating needle driver 68 also rotates hollow needle 86 so that it boresinto the tissue to be ablated. When properly in position, an appropriateliquid, such as ethanol, can be infused into the tissue to be ablatedthrough infusion port 66, infusion fluid tube 92, hollow needle 86, andinto the tissue. Since the tip 100 of hollow needle 86 is buried withinthe tissue to be ablated, the operator is assured that the ablationliquid is delivered to the proper place while minimizing ablation ofsurrounding tissue.

Turning now to FIG. 8, the distal end 102 of a catheter of the presentinvention is shown. The hollow corkscrew infusion needle 104 is movablypositioned within flexible distal tube 106. The flexible tube 106 allowsmovement of the distal end 102 in response to the steering mechanism112. The steering mechanism 112 is conventional and functions as isknown in the art. The distal end 102 also comprises mapping electrodes108 which monitor electro activity of the heart muscle as describedabove. The mapping electrodes are connected through signal wires 111 tostandard multichannel EKG machine as is known in the art.

The braided torque tube 114 is connected to the inside diameter of theinfusion needle 104 and provides means for rotating the infusion needle104 about the longitudinal axis 105 of the catheter and moving theneedle 104 axially within the distal tube 106. The braided torque tube114 consists of standard flexible tubing overlapped with a wire braidwhich stiffens the tube and allows torquing of the tube to rotate theneedle 104.

FIG. 9 shows the handle assembly 115 of a catheter of the presentinvention. The braided torque tube 114 is connected to an infusionneedle advance/retract knob 116 by which the user controls axialmovement of the infusion needle 104. A female luer lock infusion port ispositioned on the advance/retract knob 116. A standard strain reliefmeans 118 prevents kinking of the flexible tube 119. Also provided is ahandle 120 secured to the catheter through front handle support 122 andrear handle support 124. The handle assembly 115 is attached to astandard steering/mapping catheter handle 130 as is conventional andsignal wires 132 are connected to the appropriate receiving units.

FIGS. 10A through 10C show the distal end 134 of a catheter comprisingan infusion needle 136 connected to a braided torque tube 138 asdescribed above. The distal tube 142 also comprises an elastomeric seal152 made from standard materials well known to those of skill in theart. The elastomeric seal 152 provides a seal for the distal tube 142and prevents blood from flowing into the lumen of the catheter.Typically, the infusion needle 136 is coated with a compound such asmold release, to facilitate movement of the needle through theelastomeric seal 152.

Also included in this embodiment is a set of spring loaded pre-curvedanchoring needles 144 positioned near the outer edge of the distal tube142. The anchoring needles are attached to a shuttle 150 and compressionspring 146 which are triggered through pull wires 148 through a triggerdevice on the handle. The function of the trigger device is shown morefully in FIGS. 13A, 13B and 14.

FIG. 10B shows the extended anchoring needles 144 after the triggeringdevice has released the shuttle 150 and compression spring 146. Thismechanism permits the distal end of the catheter to be attached in analmost instantaneous fashion and eliminates the effects of cardiacmotion on the attachment procedure. FIG. 10C is an end view of thedistal end 134 showing the position of the pre-curved anchoring needles144 after release. In the embodiment shown here, the anchoring needles144 are curved towards the longitudinal axis of the catheter. Theanchoring needles 114, however, can be curved towards or away from thelongitudinal axis.

FIGS. 11A and 11B show a further embodiment of the catheter comprisinganchoring needles 162 which are used for infusion as well as anchoring.In this embodiment, the needles 162 are connected to infusion channel160 through which the ablation liquid or other compound is delivered tothe infusion needles 162. The infusion needles 162 are shown in theextended position after the shuttle 166 and compression spring 164 havemoved the needles 162 axially through the distal tube 156. As with otherembodiments, map electrodes 154 can be used to create an electrophysiological map of the tissue. Braided tube 158 is used to anchor thecompression spring 164. The infusion needles are curved outward as wellas inward in this embodiment (FIG. 11B).

FIG. 12 is an end view of the distal end 168 of a catheter of theinvention showing the arrangement of infusion needles 170 in which fiveneedles project away from the longitudinal axis and five project towardthe axis.

FIGS. 13A and 13B illustrate the trigger assembly by which thepre-curved needles 200 are released from the distal end 202 of thecatheters of the present invention. FIG. 13A shows the pre-curvedneedles 200 in the retracted position within the flexible distal tube204. The pre-curved needles 200 are attached to the shuttle 206 which isheld in place by three trigger tabs 208, two of which are illustrated inFIG. 13A. The trigger tabs 208 are permanently fixed to the front stop210 and pre-loaded against the inner diameter 212 of the distal tube204.

As in the other embodiments disclosed above, the pre-curved needles 200are fluidly connected to infusion channel 214, which enters the flexibledistal tube distal 204, through braided tube 211. Map electrodes 216 areused to create an electro physiological map of the heart as described.

FIG. 13B shows the pre-curved needles 200 in the extended position afterthe trigger tabs 208 have been pulled towards the longitude axis of thecatheter by the trigger pull wires 220. Once the trigger tabs 208 havebeen pulled towards the longitude axis, the shuttle 206 is released andthe compression spring 222 drives the shuttle 206 and needles 200rapidly towards the distal tip of the catheter. The inertia of thecatheter body prevents the tip from withdrawing and needles 200 aresubsequently driven into the target tissue. FIG. 13B also shows theposition of the trigger tabs 208 an the inner diameter of the shuttle206 after the shuttle 206 has moved forward. After use the shuttle pullwires 218 are activated to pull the pre-curved needles 200 to theretracted position.

FIG. 14A shows the handle assembly 230 comprising a handle body 232 fromwhich this position and ablation tip steering lover 234. The handle body232 comprises a needle trigger 236 Which is shown in both the cocked andfired (dashed lines) positions. The distal end of the trigger wires 238are attached between the distal end 240 and the pivot point 242 toinsure the wires 238 are pulled when the lever is pulled. The retractor244 is shown in the cocked and fired (dashed lines) positions, as well.The pull wires 244 are attached between the pivot point 246 and thedistal end of the retractor 248 as for the trigger. The handle assemblyincludes a lead 250 which allows for connection to appropriate ablationcompound as described above.

Modification and variation can be made to the disclosed embodimentswithout departing from the subject of the invention as defined in thefollowing claims.

1. A method for delivering a therapeutic compound to an endocardialdelivery site, said method comprising: advancing an elongated catheterbody comprising at least one electrode and a hollow penetratingstructure into a cardiac chamber; sensing and selecting an area fortreatment by measuring electric signals within the cardiac chamber;correlating the electric signals with an electrophysiological map; anddelivering the therapeutic compound into the cardiac tissue through thehollow penetrating structure.
 2. The method as in claim 1, wherein theat least one electrode comprises a plurality of electrodes.
 3. Themethod as in claim 2, wherein the plurality of electrodes comprise aplurality of ring electrodes on the elongated catheter body.
 4. Themethod as in claim 2, wherein the plurality of electrodes comprise a tipelectrode on the catheter body.
 5. The method as in claim 1, furthercomprising steering the catheter to engage the location of theendocardial delivery site.
 6. The method as in claim 5, wherein steeringcomprises pulling cables to steer a distal portion of the catheter body.7. The method as in claim 1, further comprising securing the end of thehollow penetrating structure into tissue at the endocardial deliverysite while the therapeutic compound is being delivered.